The C/F wider rear link mount has been used by the team to add roll stiffness but in a different way to the usual. It has allowed the car to use a softer spring and a longer camber link position on the hub carrier. 
The team has found that this will keep the car flatter in the turn. It has 2 widths, the widest being for carpet as it is the most aggressive on initial steering and then the narrow setting for astro.

Definitely worth having available as a tuning aid.